Fixed all known bugs

Hey Surgeons! 

Quick patch to fix some things I knew about from the game jam, but didn't have time to fix.

Here's the changes:

-There's now an arrow that helps new players figure out to click the opening paper.

-Shadows have been added to a lot of objects, so the game looks a lot better.

-Reworked the sfx systems so every single medication / surgery has sound effects

-Fixed Amputation to work properly, with no graphical artifacts.

-Patients now arrive and leave quicker.

-Fixed some broken logic on Replace Limb, which would cause limbs to be much more predictable than intended.

That's pretty much it! Enjoy!